Demographics
The suburbs, surrounded by easily annexed flat ground, have been expanding at a tremendous rate since the early 1960s. Aurora, Elgin, Joliet, and Naperville are noteworthy for being four of the few boomburbs outside the Sun Belt, West Coast and Mountain States regions, and exurban Kendall County ranked as the fastest-growing county (among counties with a population greater than 10,000) in the United States between the years 2000 and 2007.
Settlement patterns in the Chicago metropolitan area tend to follow those in the city proper: the northern suburbs along the shore of Lake Michigan are comparatively affluent, while the southern suburbs (sometimes known as Chicago Southland) are less so, with lower median incomes and a lower cost of living. However, there is a major exception to this. While Chicago's West Side is the poorest section of the city, the western and northwestern suburbs contain many affluent areas. According to the 2000 Census, DuPage County had the highest median household income of any county in the Midwestern United States.
According to the 2000 U.S. Census, poverty rates of the largest counties from least poverty to most are as follows: McHenry 3.70%, Dupage 5.9%, Will 6.7%, Lake 6.9%, Kane 7.4%, Cook 14.5%.
In an in-depth historical analysis, Keating (2004, 2005) examined the origins of 233 settlements that by 1900 had become suburbs or city neighborhoods of the Chicago metropolitan area. The settlements began as farm centers (41%), industrial towns (30%), residential railroad suburbs (15%), and recreational/institutional centers (13%). Although relations between the different settlement types were at times contentious, there also was cooperation in such undertakings as the construction of high schools.
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